Apparatus and method for preventing spams in voip system

ABSTRACT

A system for preventing a spam-call for a VoIP system includes a communication network, a plurality of terminals connected via the network, and a server. The server includes a server black list DB, a connection control module, a membership information management module, and a server-side management module. Each of the terminals includes a terminal-side management module. With the system, VoIP spam can be prevented in a cost-effective way and users&#39; convenience can be increased.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of PCT/KR2008/003720 filed on Jun.27, 2008, which claims the benefit of Korean Application No.10-2007-0065637 filed Jun. 29, 2007, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a system and method for preventingvoice over IP (hereinafter referred to as ‘VoIP’) spam calls(hereinafter referred to as ‘spam’).

BACKGROUND ART

As Internet communication technology advances rapidly, the number ofInternet network-based telephone users have increased. VoIP spamproliferating unwanted and unilateral information has also increased,which becomes a serious issue. Various methods for preventing VoIP spamhave been proposed as follows.

(A) Contents filtering method: This method, a general type of a spamprevention method used in e-mail spam, filters spam information bychecking contents. However, in case of VoIP, contents cannot bedetermined until a VoIP user or a VoIP service provider answers a call.Further, In case of contents comprising voice and video, there is adifficulty in determining whether the contents are spam or not becausethe voice and video recognition technology is not elaborate so far.

(B) Blacklist-based method: This method prevents spam through addressmapping by registering spammers to form a blacklist thereof. However,this method may not properly handle the situation where registeredspammers are normal users and may not effectively update a blacklist.Further, this method has a disadvantage in that it does not reflect thecharacteristic of VoIP users since the management of a blacklist isconcentrically maintained by a server.

(C) Whitelist-based method: This method is an opposite method to theblacklist-based method and receives only incoming calls from validusers. However, in this method, if a sender is not registered with awhitelist (e.g., when the sender first communicates with a VoIP user),it cannot communicate with the user.

(D) Consent-based communication method: In this method, a user A whowants to communicate with a user B must obtain the user B′s consent. Theuser B who has given its consent to the user A may be able to accept orreject the user A's subsequent request for consent. This method,however, cannot prevent a consent request from bothering users.

(E) Reputation system-based method: This method helps to block spammersbased on the degree of reputation. For example, when a user presses aparticular button on a telephone unit in a predetermined way, thesender's id is transmitted to a central reputation system to beregistered. Ids that have been reported in a preset number aredetermined as spammers and will be blocked. In this method, however,innocent users can be registered as spammers through conspiracy.

There is thus a need for technology to prevent VoIP spam in acost-effective way while increasing users' convenience.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY OF THE DISCLOSURE

In one aspect, the present invention provides a system for preventingVoIP spam. The system according to an embodiment includes acommunication network, a plurality of terminals including at least onereceiving terminal and at least one sending terminal which are connectedvia the communication network, and a server.

The server may include a server blacklist DB, a connection controlmodule, a membership information management module, and a server-sidemanagement module.

The server blacklist DB may store numbers of sending terminals that havebeen reported as spam by at least one receiving terminal. The connectioncontrol module may, in response to a signal of request for callconnection from a sending terminal, transfer the call connection requestsignal to a receiving terminal when the number of the sending terminaldoes not exist in the server blacklist DB while rejecting the callconnection request signal when the sending terminal number exists in theserver blacklist DB. The membership information management module maystore/manage membership information including the numbers and IPs of theterminals. The server-side management module may store/manage onlysending terminal numbers that have been reported as spam by at least onereceiving terminal, or store/manage sending terminal numbers and spamreport time points in the server blacklist DB.

Each of the receiving terminals may include a terminal-side managementmodule for receiving a spam report signal input by the user of each ofthe receiving terminals, and transferring the spam report signal to theserver-side management module.

In another aspect, the present invention provides a method forpreventing VoIP spam using the above-described system. The methodaccording to an embodiment may include the steps of: (a) allowing theserver to receive a signal of request for call connection from a sendingterminal; (b) transferring the call connection request signal to thereceiving terminal when the sending terminal number does not exist inthe server blacklist DB while rejecting the call connection requestsignal when the sending terminal number exists in the server blacklistDB; and (c) storing only the sending terminal number or both the sendingterminal number and the spam report time point in the server blacklistDB when the spam report signal is received from the receiving terminal.

In accordance with the present invention, it is possible to cope withVoIP spam through participation of VoIP users. Accordingly, expenses forpreventing VoIP spam can be reduced significantly. Further, inaccordance with the present invention, transfer of sound/videopre-recorded information that is clearly found as spam can be blocked.Accordingly, the load of an overall VoIP system can be decreased andusers' convenience can be increased.

It is understood that the term ‘terminal’ refers to any type of a VoIPdevice. For example, it may be a stand-alone type telephone unit, acomputer in which a program for VoIP is executed and which is equippedwith the headset, and so on. It is also understood that the term server'refers to any type of server that can be used for preventing VoIP spam.The server can be realized in may ways. For example, the server may be aphysically independent server and may also be a part of the function ofa typical operating server for the VoIP.

The above and other aspects, features, and advantages of the presentinvention will be apparent from or are set forth in more detail in theaccompanying drawings, which are incorporated in and form a part of thisspecification, and the following Detailed Description, which togetherserve to explain by way of example the principles of the presentinvention.

BRIEF DESCRIPTION OF DRAWINGS

The above and other features of the present invention will now bedescribed in detail with reference to certain exemplary embodimentsthereof illustrated the accompanying drawings which are givenhereinbelow by way of illustration only, and thus are not limitative ofthe present invention, and wherein:

FIG. 1 is a schematic configuration of an system for preventing aspam-call for a VoIP system in accordance with a first embodiment of thepresent invention;

FIG. 2 is a flowchart illustrating a method for preventing spam-call bythe system of FIG. 1;

FIG. 3 is a schematic configuration of a system for preventing aspam-call for a VoIP system in accordance with a second embodiment ofthe present invention;

FIG. 4 is a flowchart illustrating a method for preventing spam-call bythe system of FIG. 3;

FIG. 5 is a schematic configuration of a system for preventing aspam-call for a VoIP system in accordance with a third embodiment of thepresent invention;

FIG. 6 is a flowchart illustrating a method for preventing spam-call bythe system of FIG. 5;

FIG. 7 is a schematic configuration of a system for preventing aspam-call for a VoIP system in accordance with a fourth embodiment ofthe present invention;

FIG. 8 is a flowchart illustrating a method for preventing spam-call bythe system of FIG. 7;

FIG. 9 is a schematic configuration of a system for preventing aspam-call for a VoIP system in accordance with a fifth embodiment of thepresent invention;

FIG. 10 is a flowchart illustrating a method for preventing spam-call bythe system of FIG. 9; and

FIG. 11 is a flowchart illustrating another method for preventingspam-call by the system of FIG. 9.

Reference numerals set forth in the Drawings includes reference to thefollowing elements as further discussed below:

110: receiving terminal

111: call control module

112: terminal blacklist DB

113: terminal whitelist DB

114: terminal-side management module

115: membership information management module

116: membership information DB

120: server

121: connection control module

122: pre-filtering module

123: server blacklist DB

124: server whitelist DB

125: server-side management module

DETAILED DESCRIPTION OF THE DISCLOSURE

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the drawings attachedhereinafter, wherein like reference numerals refer to like elementsthroughout. The embodiments are described below so as to explain thepresent invention by referring to the figures.

(1A) System According to a First Embodiment

A spam-call prevention system in accordance with the present inventionincludes a communication network, a plurality of terminals connected viathe network, and a server.

In an embodiment, as shown in FIG. 1, the server 120 includes aconnection control module (CCM) 121, a server blacklist DB (SB-DB) 123,a membership information management module (IMM) 115, and a server-sidemanagement module (SMM) 125.

The server blacklist DB 123 may store sending terminal numbers that havebeen reported as spam by at least one receiving terminal 110.

The connection control module 121 may, when there is a signal of requestfor call connection from a sending terminal, transfer the callconnection request signal to a receiving terminal 110 when the sendingterminal number does not exist in the server blacklist DB 123. It, onthe other hand, may reject the call connection request signal when thesending terminal number exists in the server blacklist DB.

The membership information management module 115 may store/managemembership information that includes the numbers and IPs of theterminals. The server 120 may include a membership information DB (I-DB)116 for storing the membership information.

The server-side management module 125 may store/manage sending terminalnumbers that have been reported as spam by at least one receivingterminal 110, and store/manage information about the sending terminalnumbers and/or spam report time points in the server blacklist DB 123.

Meanwhile, each of the terminals 110 includes a terminal-side managementmodule (TMM) 114 for receiving a spam report signal and transfers thespam report signal to the server-side management module.

In more detail, when there is a call connection request signal from asending terminal to a receiving terminal, the connection control module121 first searches the server blacklist DB 123 in order to check whetherthe sending terminal number exists in the server blacklist DB 123. If,as a result of the search, the sending terminal number does not exist inthe server blacklist DB 123, the connection control module 121 transfersthe call connection request signal to the receiving terminal 110. If, onthe other hand, the sending terminal number exists in the serverblacklist DB 123, the connection control module 121 denies the callconnection request.

The server-side management module 125 may manage the server blacklist DB123. That is, the server-side management module 125 stores/managessending terminal numbers that have been reported as spam by at least onereceiving terminal 110. Preferably, it stores/manages sending terminalnumbers and/or spam report time points in the server blacklist DB 123.

The server blacklist DB 123 may store sending terminal numbers that havebeen reported as spam by at least one receiving terminal 110. It is tobe understood that the sending terminal numbers may suitably beautomatically input to a blacklist stored in the server blacklist DB123, and evident spam may suitably be manually input to the blacklist byan administrator.

Meanwhile, a sending terminal number that has been reported as spam canbe subsequently treated as non-spam. In order to facilitate thetreatment, in the case in which a sending terminal number is reported asspam by any receiving terminal 110, not only the sending terminal numberbut also information about the time point when the spam was reported maybe stored in the server blacklist DB 123, and the sending terminalnumber may automatically be deleted from the server blacklist DB 123 ifa call connection request has not been made from the sending terminalnumber for a predetermined period of time.

The terminal-side management module 114 may receive the spam reportsignal and transfer the spam report signal to the server-side managementmodule 125. More particularly, when the number of a sending terminalthat has requested call connection to the receiving terminal 110 throughthe server 120 does not exist in the server blacklist DB 123, the callconnection request signal is transferred to the receiving terminal 110.In the case in which a user of the receiving terminal 110 who hasreceived the call confirms that the sending terminal number is a spamnumber and reports the spam number via, for example, a method ofpressing a spam report button after finishing a call, the terminal-sidemanagement module 114 transfers the signal to the server-side managementmodule 125 so that the sending terminal number is stored in the serverblacklist DB 123. Preferably, when transferring the spam report signal,the terminal-side management module 114 may transfer the spam reportsignal to the server 120 along with the sending terminal number.However, in the case in which information of the sending terminal numberis stored (temporarily) in the server 120, suitably, it may transferonly the spam report signal.

(1B) Method According to a First Embodiment

The present invention provides a method of preventing VoIP spam usingthe above-described system (1A). In an embodiment of the presentinvention, the method may include the steps of (a) allowing the server120 to receive a signal of request for call connection from a sendingterminal; (b) transferring the call connection request signal to thereceiving terminal 110 when the sending terminal number does not existin the server blacklist DB 123 while rejecting the call connectionrequest signal when the sending terminal number exists in the serverblacklist DB 123; and (c) after a spam report signal is received fromthe receiving terminal 110, storing the sending terminal number in theserver blacklist DB 123.

The method is described in detail with reference to FIG. 2. In step 101,the server 120 receives a call (communication) connection request signalfrom a sending terminal. In step 102, the server 120 searches the SB-DBin order to determine whether to accept the call connection request. If,as a result of the search, the number of the sending terminal exists inthe SB-DB, the server 120 rejects the call connection request (step103). If, on the other hand, the number of the sending terminal does notexist in the SB-DB, the server 120 transfers the call connection requestsignal to the receiving terminal 110.

The user of the receiving terminal 110, after the call connection occurs(preferably, after the call is answered and finished) (step 104), mayreport the sending terminal number as spam. The spam report can be madein various ways. As an example, the user can push a button provided inthe receiving terminal for spam report. The receiving terminal 110determines whether there is a spam report (step 105). If it isdetermined that there is a spam report, the receiving terminal 110transfers the spam report signal to the server 120 so that the sendingterminal number is stored in the SB-DB (step 107). If, on the otherhand, it is determined that there is no spam report, the receivingterminal 110 takes no action (step 106).

Preferably, information about the time point when a spam report wasreceived may be stored in the server blacklist DB 123 as well as thesending terminal number such that the sending terminal number can bedeleted from the server blacklist DB 123 where a call connection requesthas not been made for a predetermined period of time.

On the other hand, the information about the sending terminal numberthat is call connected to the specific receiving terminal 110 can bestored in the server 120. A detailed spam report signal may comprise a‘spam telephone number and information, indicating that the spamtelephone number is spam’ or may comprise simply ‘information indicatingthat a recently call-connected sending terminal number is spam.’

(2A) System According to a Second Embodiment

In some cases, a sending terminal number can be mistakenly orerroneously reported as spam or a user (called party) of a receivingterminal may want to change the record of a sending terminal number thathas been reported as spam to non-spam.

To this end, a system according to a second embodiment of the presentinvention is provided. As shown in FIG. 3, the system of the secondembodiment includes additional constituent(s) and resulting function(s)compared to the system of the first embodiment. The features differentfrom the first embodiment will be described while the same features asthose of the first embodiment are omitted.

In particular, the server 120 further includes a server whitelist DB(SW-DB) 124. The SW-DB may store evident non-spam sending terminalnumbers. Preferably, the evident non-spam sending terminal numbers maybe manually confirmed by a user/operator. The server-side managementmodule 125 further includes a function of disregarding a spam report fora sending terminal number when the sending terminal number exists in theSW-DB 124.

(2B) Method According to a Second Embodiment

The present invention provides a method of preventing VoIP spam usingthe above-described system (2A). In an embodiment of the presentinvention, the method may include the steps of (a) allowing the server120 to receive a call connection request signal from a sending terminal;(b) transferring the call connection request signal to the receivingterminal 110 when the sending terminal number exists only in the serverwhitelist DB 124 or both in the server whitelist DB 124 and in theserver blacklist DB 123 while rejecting the call connection requestsignal when the sending terminal number exists in the server blacklistDB 123; (c) in the case in which a spam report signal is received fromthe receiving terminal 110, disregarding the spam report when thesending terminal number exists in the server whitelist DB 124 whilestoring the sending terminal number, or both the sending terminal numberand a spam report time in the server blacklist DB 123 when the sendingterminal number does not exist in the server whitelist DB 124.

The method is described in detail with reference to FIG. 4. First, instep 201, the server 120 receives a call (communication) connectionrequest signal from a sending terminal. Next, the server 120 searchesthe SW-DB in order to determine whether to accept the call connectionrequest (step 202). If, as a result of the search, the number of thesending terminal exists in the SW-DB, the server 120 transfers the callconnection signal to the receiving terminal 110. If, on the other hand,the number of the sending terminal does not exist in the SW-DB, theserver 120 then determines whether the sending terminal number exists inthe SB-DB (step 203). If, as a result of the determination, the sendingterminal number exists in the SB-DB, the server 120 rejects the callconnection request (step 204). If, on the other hand, the sendingterminal number does not exist in the SB-DB, the server 120 transfersthe call connection request signal to the receiving terminal 110.

After the sending terminal is call connected to the receiving terminal110 (step 205), the receiving terminal 110 determines whether there is aspam report signal from a called party, as described above (step 206).If, as a result of the determination, there is a spam report signal, thereceiving terminal 110 transfers the spam report signal to the server120. If, on the other hand, there is no such spam report signal, thereceiving terminal 110 takes no action (step 207).

The SMM of the server 120, after receiving the spam report signal,determines whether the sending terminal number reported as spam existsin the SB-DB (step 208). If, as a result of the determination, thenumber exists in the SB-DB, the SMM takes no action (step 209). If, onthe other hand, the number does not exist in the SB-DB, the SMM storesthe number in SB-DB (step 210).

(3A) System According to a Third Embodiment

In some cases, a sending terminal number that is generally non-spamstill can be spam with respect to only a particular receiving terminal(user) or a particular group of terminals (users), in which a call maynot be connected to the other receiving terminals or the other groups ofreceiving terminals.

To this end, a system according to a third embodiment of the presentinvention is provided. As shown in FIG. 5, the system of the thirdembodiment includes additional constituent(s) and resulting function(s)compared to the system of the first embodiment. The features differentfrom the first embodiment will be described while the same features asthose of the first embodiment are omitted.

More specifically, the receiving terminal 110 further includes a callcontrol module (LCM) 111 and a terminal blacklist DB (TB-DB) 112 forstoring/managing spam sending terminal numbers.

In response to a call connection request signal received from theconnection control module 121, the call control module 111 may generatea called signal such as ring tome or vibration if the sending terminalnumber does not exist in a terminal blacklist DB (TB-DB) 112 whilerejecting the call connection request signal if the sending terminalnumber exists in the terminal blacklist DB 112. In addition, the callcontrol module 111 may transmit a spam report signal to theterminal-side management module 114 if the spam report signal isreceived from a user after call connection occurs.

The terminal-side management module 114 further includes a function ofstoring a sending terminal number in the terminal blacklist DB 112 whena spam report signal is received after a call from the call controlmodule 111.

Preferably, the terminal blacklist DB 112 may be disposed in thereceiving terminal 110. Also preferably, the call control module 111 maybe disposed in the receiving terminal 110.

(3B) Method According to a Third Embodiment

The present invention provides a method of preventing VoIP spam usingthe above-described system (3A). In an embodiment of the presentinvention, the method may include the steps of: (a) allowing the serverto receive a call connection request signal from a sending terminal; (b)transferring the call connection request signal to the receivingterminal when the sending terminal number does not exist in the serverblacklist DB while rejecting the call connection request signal when thesending terminal number exists in the server blacklist DB; (c)transferring a call connection request signal from the connectioncontrol module to the receiving terminal when the sending terminalnumber does not exist in the terminal blacklist DB while rejecting thecall connection request signal when the sending terminal number existsin the terminal blacklist DB; (d) when the spam report signal isreceived from a user after call connection occurs, transferring a spamreport signal to terminal management module and storing the sendingterminal number in terminal blacklist DB; and (e) storing only thesending terminal number or both the sending terminal number and the spamreport time in the server blacklist DB when a spam report signal isreceived from the receiving terminal.

That is, as shown FIG. 6, the method further includes a step 301 ofsearching the TB-DB between the steps 102 and 104 of the method (1B) anda step 303 of storing a spam number in the TB-DB between the steps 105and 107 of the method (1B).

In more detail, when a call connection request signal is received fromthe connection control module 121, the TB-DB is searched for a sendingterminal number (step 301). If, as a result of the search, the sendingterminal number does not exist in the terminal blacklist DB 112, acalled signal, such as a ring tone or vibration, is generated so that auser can answer the call (step 104). If, on the other hand, the sendingterminal number exists in the terminal blacklist DB 112, the callconnection request is rejected (step 302).

Further, when it is determined that a spam report signal is received(step 105), the spam report signal is transmitted to the terminal-sidemanagement module 114 and a sending terminal number is stored in theTB-DB (step 303).

The description of the remaining steps is omitted since they areidentical to those of the method (1B).

(4A) System According to a Fourth Embodiment

In some cases, the user of a receiving terminal may want tohandle/manage the records of sending terminal numbers. For this purpose,a system according to a fourth embodiment of the present invention isprovided. As shown in FIG. 7, the system of the fourth embodimentincludes additional constituent(s) and resulting function(s) compared tothe system of the third embodiment. The features different from thefirst embodiment will be described while the same features as those ofthe third embodiment are omitted.

That is, the terminal of the present system further includes a terminalwhitelist DB (TW-DB) 113. The TW-DB 113 may store non-spam sendingterminal numbers, for example, a ‘personal telephone directory’ manuallyinput to a terminal by a user.

The call control module 111 further includes a function of, in responseto a call connection request signal received from the connection controlmodule 121, generating a called signal when the sending terminal numberexists in the terminal whitelist DB 113 or does not exist in theterminal blacklist DB 112 while rejecting the call connection requestsignal when the sending terminal number exists in the blacklist DB.

In addition, the terminal-side management module 114 further includes afunction of storing a sending terminal number in the terminal whitelistDB 113 when a spam report signal is not received after call connection.

(4B) Method According to a Fourth Embodiment

The present invention provides a method of preventing VoIP spam usingthe above-described system (4A). As shown in FIG. 8, the method furtherincludes a step 401 of searching the TW-DB between the steps 102 and 301of the method (3B) and step 402 of managing the TW-DB.

As shown, when a call connection request signal is received from theconnection control module 121, the terminal whitelist DB 113 is searchedin order to determine whether a sending terminal number exists in theterminal whitelist DB 113 (step 401). If, as a result of the search, thesending terminal number exists in the terminal whitelist DB 113, a callconnection is established (i.e., a called signal is generated) (step104). If, on the other hand, the sending terminal number does not existin the TW-DB 113, the process proceeds to the step 301 of searching theterminal blacklist DB 112.

Before or after a spam report signal is checked (step 105) (although thelatter case is illustrated in the drawing), a step 402 of querying auser of the receiving terminal 110 as to whether a sending terminalnumber will be stored in the terminal whitelist DB 113 (this can be apersonal telephone directory), a step 403 of, when a signal indicatingthat the sending terminal number will be stored in the terminalwhitelist DB 113 is received, storing the sending terminal number in theterminal whitelist DB 113, and a step 106 of, when the stored signal isnot input, taking no action are performed separately.

Meanwhile, if a spam report signal is not received after call connectionoccurs, the sending terminal number may be automatically stored in theterminal whitelist DB 113 (not shown).

Although not shown, a user may directly manage the TW-DB through aterminal key entry.

The description of the remaining steps is omitted since they areidentical to those of the method (3B).

(5A) System According to a Fifth Embodiment

Typically, a spam call, like a spam email, is transmitted massively andrandomly. Transmitted information is generally unidirectionalinformation that is voice- or video-recorded in advance. Accordingly, itis preferred to treat information, which is received from a sendingterminal that makes a call connection request for the first time or atspecific time intervals, as spam by checking whether the information isunidirectional information.

To this end, a system according to a fifth embodiment of the presentinvention is provided. As shown in FIG. 9, the system of the fourthembodiment includes additional constituent(s) and resulting function(s)compared to the systems of the first to third embodiments. The featuresdifferent from the first embodiment will be described while the samefeatures as those of the first to third embodiments are omitted.

That is, the server 120 of the present system further includes apre-filtering module (PFM) 122 as well as a server whitelist DB 124.

The server whitelist DB 124 may store sending terminal numbers that areevidently or likely non-spam or sending terminal numbers that have beenconnected to the receiving terminal 110 but have not been reported asspam.

The pre-filtering module 122 is operated when the sending terminalnumber does not exist in both the server blacklist DB 123 and the serverwhitelist DB 124. It may generate a question based on voice or videoinformation which can be recognized by a person in order to checkwhether a mechanical device operates the sending terminal to transmitsuch information, and request an answer from a sending terminal bysending the question to the sending terminal. When a correct answer isreturned from the sending terminal, the sending terminal number isdetermined as non-spam. On the other hand, when the answer is notreturned or when an incorrect answer is returned from the sendingterminal, the sending terminal number is determined as spam and thesending terminal number is transmitted to the server-side managementmodule 125.

Preferably, the pre-filtering module 122 may add various voice, videoand/or noise in order to prevent the sending terminal from mechanicallyrecognizing the question.

The connection control module 121 further includes a function ofoperating the pre-filtering module 122 when the sending terminal numberexists in both the server blacklist DB 123 and the server whitelist DB124.

The server-side management module 125 further includes a function ofstoring a sending terminal number in the server whitelist DB 124 or theserver blacklist DB 123 based on information received from thepre-filtering module 122.

Meanwhile, in order to prevent evident non-spam sending terminals frombeing stored in the SB-DB, the server-side management module 125 maypreferably further include a function of disregarding a spam report whena sending terminal number that has been reported as spam by anyreceiving terminal 110 exists in the server whitelist DB 124.

(5B) Method According to a Fifth Embodiment

The present invention provides a method of preventing VoIP spam usingthe above-described system (5A). In an embodiment of the presentinvention, the method may include the steps of (a) allowing the server120 to receive a call connection request signal from a sending terminal;(b) allowing the server 120 to reject the call connection request signalwhen the sending terminal number exists in the server blacklist DB 123while transmitting the call connection request signal to the receivingterminal 110 when the sending terminal number does not exist in theserver blacklist DB 123 but exists in the server whitelist DB 124; and(c) when a spam report signal is received from the receiving terminal110, allowing the server 120 to store the sending terminal number orboth the sending terminal number and spam report time point in theserver blacklist DB 123.

That is, the method may further include generating a question based onvoice or video information and requesting an answer from the sendingterminal by forwarding the question to the sending terminal, when thesending terminal number does not exist in the server blacklist DB nor inthe server whitelist DB, and storing the sending terminal number in theserver whitelist DB 124, and transferring the call connection requestsignal to the receiving terminal 110 when a correct answer is returnedfrom the sending terminal while storing the sending terminal number inthe server blacklist DB 123, and rejecting the call connection requestwhen the answer is not returned from the sending terminal or anincorrect answer is returned from the sending terminal

The method is described in detail with reference to FIG. 10. First, instep 501, the server 120 receives a call (communication) connectionrequest signal from a sending terminal. The server 120 searches theSB-DB in order to determine whether to reject the call connectionrequest signal (step 502). If, as a result of the search, the sendingterminal number exists in the SB-DB, the server 120 rejects the callconnection request (step 503). If, on the other hand, the sendingterminal number does not exist in the SB-DB, the server 120 proceeds toa step 504 of searching the SW-DB. If, as a result of the search for theSW-DB in step 504, the sending terminal number exists in the SW-DB, theserver 120 transmits the call connection request signal to the receivingterminal 110. If, on the other hand, the number of the sending terminaldoes not exist in the SW-DB, the server 120 proceeds to a step 505.

The step 505 is a pre-filtering step in which a question is generated asvoice or video, an answer is requested from the sending terminal bysending the generated question to the sending terminal, and whether acorrect answer is returned from the sending terminal is determined orwhether the answer is not returned from the sending terminal or anincorrect answer is returned from the sending terminal is determined.When the correct answer is returned from the sending terminal, theserver 120 stores the sending terminal number in the server whitelist DB124 (step 506) and transmits the call connection request signal to thereceiving terminal 110. When the answer is not returned from the sendingterminal or an incorrect answer is returned from the sending terminal,the server 120 stores the sending terminal number in the serverblacklist DB 123 (step 107) and rejects the call connection request(step 503).

Further detailed description of the steps 504 and 506 is omitted sincethey are identical to the steps 401 and 301 of the method (4B).Meanwhile, a spam prevention method employing the system having thefunction of disregarding a spam report is described with regard to FIG.11.

The spam prevention method is identical to FIG. 10 except that the steps208, 209 and 210 shown in FIG. 4 are added between the steps 105 and 107of FIG. 10. That is, the SMM of the server 120 that has received a spamreport signal determines whether the sending terminal number reported asspam exists in the SB-DB (step 208), does not take no action when it isdetermined that the sending terminal number exists in the SB-DB (step209) while storing the sending terminal number in the SB-DB when it isdetermined that the sending terminal number does not exist in the SB-DB(step 107).

In accordance with the present invention, VoIP spam can be prevented ina cost-effective way, the load of an overall VoIP system can be reduced,and user convenience can be increased.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

1. A system for preventing VoIP spam call, the system including: acommunication network, a plurality of terminals including at least onereceiving terminal and at least one sending terminal which are connectedvia the network, and a server, wherein the server includes: (1) a serverblacklist DB for storing numbers of sending terminals that have beenreported as spam by at least one receiving terminal; (2) a connectioncontrol module for, in response to a signal of request for callconnection from a sending terminal, transferring the call connectionrequest signal to a receiving terminal when the number of the sendingterminal does not exist in the server blacklist DB, and rejecting thecall connection request signal when the sending terminal number existsin the server blacklist DB; (3) a membership information managementmodule for storing/managing membership information including the numbersand IPs of the terminals; and (4) a server-side management module forstoring/managing sending terminal numbers that have been reported asspam by at least one receiving terminal, or storing/managing sendingterminal numbers and spam report time points in the server blacklist DB,and wherein each of the receiving terminals includes a terminal-sidemanagement module for receiving a spam report signal input by the userof each of the receiving terminals, and transferring the spam reportsignal to the server-side management module.
 2. The system according toclaim 1, wherein the server further includes a server whitelist DB forstoring non-spam sending terminal numbers, and wherein the server-sidemanagement module further includes a function of disregarding the spamreport when the sending terminal number, although having been reportedas spam by at least one receiving terminal, exists in the serverwhitelist DB.
 3. The system according to claim 1, wherein each of thereceiving terminals further includes: (1) a terminal blacklist DB forstoring spam sending terminal numbers; and (2) a call control modulewhich, in response to a call connection request signal received from theconnection control module, generates a called signal when the sendingterminal number does not exist in the terminal blacklist DB whilerejecting the call connection request signal when the sending terminalnumber exists in the terminal blacklist DB, and, in response to the spamreport signal received from the user, transmits the spam report signalto the terminal-side management module, and wherein the terminal-sidemanagement module further includes a function of storing the sendingterminal number in the terminal blacklist DB when the spam report signalis received.
 4. The system according to claim 3, wherein each of thereceiving terminals further includes a terminal whitelist DB for storingnon-spam sending terminal numbers, wherein the call control modulefurther includes a function of, in response to a call connection requestsignal received from the connection control module, generating a calledsignal when the sending terminal number exists in the terminal whitelistDB or does not exist the terminal blacklist DB while rejecting the callconnection request signal when the sending terminal number exists in theterminal blacklist DB, and wherein the terminal-side management modulefurther includes a function of storing the sending terminal number inthe terminal whitelist DB when the spam report signal is not receivedafter call connection occurs.
 5. The system according to claim 1,wherein the server further includes: (1) a server whitelist DB forstoring sending terminal numbers that are evidently non-spam or have notbeen reported as spam; and (2) a pre-filtering module for (a) generatinga question based on voice or video information and requesting an answerfrom the sending terminal by forwarding the question to the sendingterminal, (b) determining that the sending terminal number as non-spamwhen a correct answer is returned while determining that the sendingterminal number as spam when the answer is not returned or when anincorrect answer is returned, and (c) transmitting the determinationresult to the server-side management module, wherein the connectioncontrol module further includes a function of operating thepre-filtering module when the sending terminal number exists in both theserver blacklist DB and the server whitelist DB, and wherein theserver-side management module further includes a function of storing thesending terminal number in the server whitelist DB or the serverblacklist DB based on determination result received from thepre-filtering module.
 6. The system according to claim 5, wherein theserver-side management module preferably further includes a function ofdisregarding the spam report when the sending terminal number exists inthe server whitelist DB.
 7. The system according to claim 3, wherein theserver further includes: (1) a server whitelist DB for storing sendingterminal numbers that are evidently non-spam or have not been reportedas spam; and (2) a pre-filtering module for (a) generating a questionbased on voice or video information and requesting an answer from thesending terminal by forwarding the question to the sending terminal, (b)determining that the sending terminal number as non-spam when a correctanswer is returned while determining that the sending terminal number asspam when the answer is not returned or when an incorrect answer isreturned, and (c) transmitting the determination result to theserver-side management module, wherein the connection control modulefurther includes a function of operating the pre-filtering module whenthe sending terminal number exists in both the server blacklist DB andthe server whitelist DB, and wherein the server-side management modulefurther includes a function of storing the sending terminal number inthe server whitelist DB or the server blacklist DB based ondetermination result received from the pre-filtering module.
 8. Thesystem according to claim 7, wherein the server-side management modulepreferably further includes a function of disregarding the spam reportwhen the sending terminal number exists in the server whitelist DB. 9.The system according to claim 4, wherein the server further includes:(1) a server whitelist DB for storing sending terminal numbers that areevidently non-spam or have not been reported as spam; and (2) apre-filtering module for (a) generating a question based on voice orvideo information and requesting an answer from the sending terminal byforwarding the question to the sending terminal, (b) determining thatthe sending terminal number as non-spam when a correct answer isreturned while determining that the sending terminal number as spam whenthe answer is not returned or when an incorrect answer is returned, and(c) transmitting the determination result to the server-side managementmodule, wherein the connection control module further includes afunction of operating the pre-filtering module when the sending terminalnumber exists in both the server blacklist DB and the server whitelistDB, and wherein the server-side management module further includes afunction of storing the sending terminal number in the server whitelistDB or the server blacklist DB based on determination result receivedfrom the pre-filtering module.
 10. The system according to claim 9,wherein the server-side management module preferably further includes afunction of disregarding the spam report when the sending terminalnumber exists in the server whitelist DB.
 11. A method for preventingVoIP spam using the system of claim 1, including the steps of: (a)allowing the server to receive a signal of request for call connectionfrom a sending terminal; (b) transferring the call connection requestsignal to the receiving terminal when the sending terminal number doesnot exist in the server blacklist DB while rejecting the call connectionrequest signal when the sending terminal number exists in the serverblacklist DB; and (c) storing only the sending terminal number or boththe sending terminal number and the spam report time point in the serverblacklist DB when the spam report signal is received from the receivingterminal.
 12. A method for preventing VoIP spam using the system ofclaim 2, including the steps of: (a) allowing the server to receive asignal of request for call connection from a sending terminal; (b)transferring the call connection request signal to the receivingterminal when the sending terminal number exists only in the serverwhitelist DB or both in the server whitelist DB and in the serverblacklist DB while rejecting the call connection request signal when thesending terminal number exists in the server blacklist DB; and (c) inthe case in which the spam report signal is received from the receivingterminal, disregarding the spam report when the sending terminal numberexists in the server whitelist DB while storing only the sendingterminal number or both the sending terminal number and the spam reporttime point in the server blacklist DB when the sending terminal numberdoes not exist in the server whitelist DB.
 13. A method for preventingVoIP spam using the system of claim 3, including the steps of: (a)allowing the server to receive a signal of request for call connectionfrom a sending terminal; (b) transferring the call connection requestsignal to the receiving terminal when the sending terminal number doesnot exist in the server blacklist DB while rejecting the call connectionrequest signal when the sending terminal number exists in the serverblacklist DB; (c) transferring the call connection request signal fromthe connection control module to the receiving terminal when the sendingterminal number does not exist in the terminal blacklist DB whilerejecting the call connection request signal when the sending terminalnumber exists in the terminal blacklist DB; (d) when a spam reportsignal is received after call connection occurs, transferring the spamreport signal to the terminal management module and storing the sendingterminal number to terminal blacklist DB; and (e) storing only thesending terminal number or both the sending terminal number and the spamreport time point in the server blacklist DB when the spam report signalis received from the receiving terminal.
 14. A method for preventingVoIP spam using the system of claim 4, including the steps of: (a)allowing the server to receive a signal of request for call connectionfrom a sending terminal; (b) transferring the call connection requestsignal to the receiving terminal when the sending terminal number doesnot exist in the server blacklist DB while rejecting the call connectionrequest signal when the sending terminal number exists in the serverblacklist DB; (c) transferring the call connection request signal fromthe connection control module to the receiving terminal when the sendingterminal number does not exist in the terminal blacklist DB whilerejecting the call connection request signal when the sending terminalnumber exists in the terminal blacklist DB; (d) (i) when a spam reportsignal is received after call connection occurs, transferring the spamreport signal to the terminal management module and storing the sendingterminal number in the terminal blacklist DB, and (ii) when the spamreport signal is not received after call connection occurs, storing thesending terminal number in the terminal whitelist DB; and (e) storingonly the sending terminal number or both the sending terminal number andthe spam report time point in the server blacklist DB when the spamreport signal is received from the receiving terminal.
 15. A method forpreventing VoIP spam using the system of claim 5, including the stepsof: (a) allowing the server to receive a signal of request for callconnection from a sending terminal; (b) (i) allowing the server toreject a call connection request-signal when the sending terminal numberexists in the server blacklist DB, (ii) transmitting the call connectionrequest signal to the receiving terminal when the sending terminalnumber does not exist in the server blacklist DB, but exists in theserver whitelist DB, and (iii) (iii-a) generating a question based onvoice or video information and requesting an answer from a sendingterminal by forwarding the question to the sending terminal, when thesending terminal number does not exist in the server blacklist DB nor inthe server whitelist DB, and (iii-b) then (iii-b-a) storing the sendingterminal number in the server whitelist DB, and transferring a callconnection request signal to the receiving terminal when a correctanswer is returned from the sending terminal, or (iii-b-b) storing thesending terminal number in the server blacklist DB, and rejecting thecall connection-request signal when the answer is not returned from thesending terminal or an incorrect answer is returned from the sendingterminal; and (c) allowing the server to store only the sending terminalnumber or both the sending terminal number and the spam report timepoint in the server blacklist DB when the spam report signal is receivedfrom the receiving terminal.
 16. The method according to claim 15,wherein the step (c), the spam report is disregarded when the sendingterminal number exists in the server whithelist DB.